1. Technical Field
The present invention relates to a data receiving circuit that performs various signal processing on a reception signal received through a transmission line, and to a semiconductor device including the data receiving circuit.
2. Description of the Related Art
In recent years, there are increasing demands for high speed, high density data transmission, and a differential transmission method is proposed as a data transmission system that can meet such demands.
In the differential transmission system, information data is converted to a pair of differential signals having polarities different from each other, and these differential signals are transmitted over balanced transmission lines. As a data receiving circuit for receiving such differential signals, there is proposed a circuit that includes a differential input stage for inputting a pair of received differential signals and a level converting stage for converting the levels of the signals inputted to the differential input stage to a level that is usable by logical circuits, wherein the level obtained by the level converting stage is outputted as a data signal (See, for example, FIG. 1 of Japanese Patent Application Laid-Open Publication No. 2008-124697). In this data receiving circuit, a pair of received differential signals (IN1, IN2) are supplied to the gate terminals of transistors M81 and M82 respectively of the differential input stage (M80 to M84) and signals obtained by amplifying a difference value between these differential signals (IN1, IN2) are supplied to the level converting stage (M85 to M88) via lines 3 and 4.
However, high speed, high density transmission may result in rounding of the waveforms of received signals (the pair of differential signals). In such cases, it is difficult to accurately obtain data signals from received signals transmitted with high-speed.